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How can a circuit not have a neutral?
Twin wire neutralHot and neutral have similar voltage to ground - finding the problemWhy do electrical systems have neutral, live and ground when electronic systems have only VCC and ground?How does having neutral make electrical systems safer than electronic systems which do not have neutral?How to overcome weak neutral from electric company?Why cut both live and neutral wires?Odd voltage readings between phase-ground, phase-neutral, neutral-groundWhy no current in neutral wire_kids questionNeutral wiring in residential homesDoes the neutral wire have any voltage?
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$begingroup$
I've been making plans to install a NEMA 6-50 outlet in my garage, but I don't understand how it can not have a neutral, and instead have two hots (at 120v each) and a ground.
What completes the circuit? My understanding is that hot provides charged particles, while the neutral gives any remaining charged particles a path back to ground.
This seems like a simple question - I've done a fair bit of searching on both this site and diy.se, but can't find any answers.
basic outlet neutral
asked 8 hours ago
CowthulhuCowthulhu
1084 bronze badges
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Cowthulhu is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
$endgroup$
add a comment |
$begingroup$
I've been making plans to install a NEMA 6-50 outlet in my garage, but I don't understand how it can not have a neutral, and instead have two hots (at 120v each) and a ground.
What completes the circuit? My understanding is that hot provides charged particles, while the neutral gives any remaining charged particles a path back to ground.
This seems like a simple question - I've done a fair bit of searching on both this site and diy.se, but can't find any answers.
basic outlet neutral
asked 8 hours ago
CowthulhuCowthulhu
1084 bronze badges
New contributor
Cowthulhu is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
$endgroup$
1
$begingroup$
"Live/hot" should be merely be taken to mean "anything that is not at ground", whereas "neutral" should be taken to mean "any that return current goes through that is tied to ground somewhere". It's just that on a wall outlet, the plug that return currents travel on which would otherwise also be "live" has been tied to ground for safety purposes making it the neutral.
$endgroup$
– DKNguyen
8 hours ago
$begingroup$
Also note that just because the neutral is connected to ground doesn't mean it necessarily sits at ground. The neutral's connection to ground may be very far away from where you are and the resulting impedance can make the neutral voltage rise if there are currents.
$endgroup$
– DKNguyen
8 hours ago
add a comment |
$begingroup$
I've been making plans to install a NEMA 6-50 outlet in my garage, but I don't understand how it can not have a neutral, and instead have two hots (at 120v each) and a ground.
What completes the circuit? My understanding is that hot provides charged particles, while the neutral gives any remaining charged particles a path back to ground.
This seems like a simple question - I've done a fair bit of searching on both this site and diy.se, but can't find any answers.
basic outlet neutral
asked 8 hours ago
CowthulhuCowthulhu
1084 bronze badges
New contributor
Cowthulhu is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
$endgroup$
I've been making plans to install a NEMA 6-50 outlet in my garage, but I don't understand how it can not have a neutral, and instead have two hots (at 120v each) and a ground.
What completes the circuit? My understanding is that hot provides charged particles, while the neutral gives any remaining charged particles a path back to ground.
This seems like a simple question - I've done a fair bit of searching on both this site and diy.se, but can't find any answers.
basic outlet neutral
basic outlet neutral
asked 8 hours ago
CowthulhuCowthulhu
1084 bronze badges
New contributor
Cowthulhu is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
asked 8 hours ago
CowthulhuCowthulhu
1084 bronze badges
New contributor
Cowthulhu is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
asked 8 hours ago
CowthulhuCowthulhu
1084 bronze badges
New contributor
Cowthulhu is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
asked 8 hours ago
CowthulhuCowthulhu
1084 bronze badges
asked 8 hours ago
CowthulhuCowthulhu
1084 bronze badges
1084 bronze badges
New contributor
Cowthulhu is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
New contributor
Cowthulhu is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
1
$begingroup$
"Live/hot" should be merely be taken to mean "anything that is not at ground", whereas "neutral" should be taken to mean "any that return current goes through that is tied to ground somewhere". It's just that on a wall outlet, the plug that return currents travel on which would otherwise also be "live" has been tied to ground for safety purposes making it the neutral.
$endgroup$
– DKNguyen
8 hours ago
$begingroup$
Also note that just because the neutral is connected to ground doesn't mean it necessarily sits at ground. The neutral's connection to ground may be very far away from where you are and the resulting impedance can make the neutral voltage rise if there are currents.
$endgroup$
– DKNguyen
8 hours ago
add a comment |
1
$begingroup$
"Live/hot" should be merely be taken to mean "anything that is not at ground", whereas "neutral" should be taken to mean "any that return current goes through that is tied to ground somewhere". It's just that on a wall outlet, the plug that return currents travel on which would otherwise also be "live" has been tied to ground for safety purposes making it the neutral.
$endgroup$
– DKNguyen
8 hours ago
$begingroup$
Also note that just because the neutral is connected to ground doesn't mean it necessarily sits at ground. The neutral's connection to ground may be very far away from where you are and the resulting impedance can make the neutral voltage rise if there are currents.
$endgroup$
– DKNguyen
8 hours ago
1
1
$begingroup$
"Live/hot" should be merely be taken to mean "anything that is not at ground", whereas "neutral" should be taken to mean "any that return current goes through that is tied to ground somewhere". It's just that on a wall outlet, the plug that return currents travel on which would otherwise also be "live" has been tied to ground for safety purposes making it the neutral.
$endgroup$
– DKNguyen
8 hours ago
$begingroup$
"Live/hot" should be merely be taken to mean "anything that is not at ground", whereas "neutral" should be taken to mean "any that return current goes through that is tied to ground somewhere". It's just that on a wall outlet, the plug that return currents travel on which would otherwise also be "live" has been tied to ground for safety purposes making it the neutral.
$endgroup$
– DKNguyen
8 hours ago
$begingroup$
Also note that just because the neutral is connected to ground doesn't mean it necessarily sits at ground. The neutral's connection to ground may be very far away from where you are and the resulting impedance can make the neutral voltage rise if there are currents.
$endgroup$
– DKNguyen
8 hours ago
$begingroup$
Also note that just because the neutral is connected to ground doesn't mean it necessarily sits at ground. The neutral's connection to ground may be very far away from where you are and the resulting impedance can make the neutral voltage rise if there are currents.
$endgroup$
– DKNguyen
8 hours ago
add a comment |
3 Answers
3
active
oldest
votes
$begingroup$
The two sides are out of phase with each other. When one side is high, the other is low, and vice versa.
This is a 240 V outlet.
answered 8 hours ago
evildemonicevildemonic
3,5981 gold badge12 silver badges29 bronze badges
$endgroup$
$begingroup$
In other words, it's kind of like a balanced three-phase system that has no neutral current and does not require a neutral, except instead of three phases there are only two.
$endgroup$
– DKNguyen
8 hours ago
$begingroup$
Note that the phases are sometimes called "hot" and "cold", though that should not be assumed to mean that "cold" is any less dangerous than hot.
$endgroup$
– Hearth
8 hours ago
$begingroup$
Thanks - that makes perfect sense.
$endgroup$
– Cowthulhu
8 hours ago
2
$begingroup$
@Hearth: that's interesting. I'd call them "hot" and "the other hot"!
$endgroup$
– TimWescott
8 hours ago
$begingroup$
@TimWescott Probably a better convention! But it is worth knowing that "cold" does not mean safe.
$endgroup$
– Hearth
7 hours ago
add a comment |
$begingroup$
tl; dr: You should install a NEMA 14-50 (4-wire: L1/L2, Neutral and Ground) instead of NEMA 6-50 for best flexibility. NEMA 14-50 is the standard 'dryer' plug now, and it's what a car charger uses too.
By the way, if you're messing with this, please consult an electrician. The fact that you're asking this at all makes me all kinds of worried.
Now, to the question. A 240V-only device has no need for a neutral since the load is connected across both ‘hot’ legs. So the current is always in balance, thus no need for a neutral to carry any imbalance. You will sometimes find this kind of wiring on high-power appliances like water heaters, ovens and fixed A/C units: two hots L1 and L2, and a Ground.
Plug-ins like dryers and electric ranges? That's a confusing story - sometimes there's just Neutral and sometimes Neutral and Ground. At the risk of drifting into DIY-land... more below.
3-wire vs. 4-wire 240V
Historically in the U.S. there have been two different types of high-current plug-in 240V appliance wiring: "3-wire" and "4-wire".
3-wire 240V has L1, L2 (hot) and Neutral. Appliances like dryers and ranges were allowed to connect Neutral to frame ground, so effectively the Neutral was serving as safety ground and carrying imbalance current if the appliance also used 120V.
Sound sketchy? It is. Even when things are working properly, when an appliance uses both 240V and 120V, the Neutral will have a small AC voltage on it due to the IR drop of the wire carrying the imbalance current. But when things go bad - say, for some reason Neutral opens up due to a flaky connection - you will have full 120V on the chassis. Not safe at all.
To remedy this fault, newer (since '96) 240V wiring uses the 4-wire system with L1, L2 (Hot), Neutral and Ground. Neutral is optional, only if the appliance needs a split 120 feed (say, for a dual-wattage heating element or a controller that runs on 120V), but it always gets a Ground. This enforces the idea that safety ground never carries current except when there's a fault, which isn't possible with the 3-wire L1/L2/Neutral setup.
More about the two 240V wiring types here: https://fredsappliance.com/service/3-prong-vs-4-prong-dryer-outlets-whats-the-difference/
And here: https://www.jadelearning.com/3-wire-cords-on-modern-4-wire-appliances/
Either way, at the panel the two hot legs L1/L2 are referred back to Neutral, as well as to safety ground. L1/L2 will have a duplex panel breaker, one breaker for each leg. The duplex breaker ensures that a hot-to-ground, hot-to-neutral or hot-to-hot fault in either leg will trip both breakers.
answered 8 hours ago
hacktasticalhacktastical
2,6414 silver badges12 bronze badges
$endgroup$
add a comment |
$begingroup$
A 240v electric water heater has the same type of wiring, 2 120v legs and a ground, as do most residential air conditioners and ovens. If the appliance doesn't need 120v for anything then they don't need the neutral.
answered 7 hours ago
JACKJACK
1684 bronze badges
$endgroup$
add a comment |
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3 Answers
3
active
oldest
votes
3 Answers
3
active
oldest
votes
active
oldest
votes
active
oldest
votes
$begingroup$
The two sides are out of phase with each other. When one side is high, the other is low, and vice versa.
This is a 240 V outlet.
answered 8 hours ago
evildemonicevildemonic
3,5981 gold badge12 silver badges29 bronze badges
$endgroup$
$begingroup$
In other words, it's kind of like a balanced three-phase system that has no neutral current and does not require a neutral, except instead of three phases there are only two.
$endgroup$
– DKNguyen
8 hours ago
$begingroup$
Note that the phases are sometimes called "hot" and "cold", though that should not be assumed to mean that "cold" is any less dangerous than hot.
$endgroup$
– Hearth
8 hours ago
$begingroup$
Thanks - that makes perfect sense.
$endgroup$
– Cowthulhu
8 hours ago
2
$begingroup$
@Hearth: that's interesting. I'd call them "hot" and "the other hot"!
$endgroup$
– TimWescott
8 hours ago
$begingroup$
@TimWescott Probably a better convention! But it is worth knowing that "cold" does not mean safe.
$endgroup$
– Hearth
7 hours ago
add a comment |
$begingroup$
The two sides are out of phase with each other. When one side is high, the other is low, and vice versa.
This is a 240 V outlet.
answered 8 hours ago
evildemonicevildemonic
3,5981 gold badge12 silver badges29 bronze badges
$endgroup$
$begingroup$
In other words, it's kind of like a balanced three-phase system that has no neutral current and does not require a neutral, except instead of three phases there are only two.
$endgroup$
– DKNguyen
8 hours ago
$begingroup$
Note that the phases are sometimes called "hot" and "cold", though that should not be assumed to mean that "cold" is any less dangerous than hot.
$endgroup$
– Hearth
8 hours ago
$begingroup$
Thanks - that makes perfect sense.
$endgroup$
– Cowthulhu
8 hours ago
2
$begingroup$
@Hearth: that's interesting. I'd call them "hot" and "the other hot"!
$endgroup$
– TimWescott
8 hours ago
$begingroup$
@TimWescott Probably a better convention! But it is worth knowing that "cold" does not mean safe.
$endgroup$
– Hearth
7 hours ago
add a comment |
$begingroup$
The two sides are out of phase with each other. When one side is high, the other is low, and vice versa.
This is a 240 V outlet.
answered 8 hours ago
evildemonicevildemonic
3,5981 gold badge12 silver badges29 bronze badges
$endgroup$
The two sides are out of phase with each other. When one side is high, the other is low, and vice versa.
This is a 240 V outlet.
answered 8 hours ago
evildemonicevildemonic
3,5981 gold badge12 silver badges29 bronze badges
answered 8 hours ago
evildemonicevildemonic
3,5981 gold badge12 silver badges29 bronze badges
answered 8 hours ago
evildemonicevildemonic
3,5981 gold badge12 silver badges29 bronze badges
answered 8 hours ago
evildemonicevildemonic
3,5981 gold badge12 silver badges29 bronze badges
3,5981 gold badge12 silver badges29 bronze badges
$begingroup$
In other words, it's kind of like a balanced three-phase system that has no neutral current and does not require a neutral, except instead of three phases there are only two.
$endgroup$
– DKNguyen
8 hours ago
$begingroup$
Note that the phases are sometimes called "hot" and "cold", though that should not be assumed to mean that "cold" is any less dangerous than hot.
$endgroup$
– Hearth
8 hours ago
$begingroup$
Thanks - that makes perfect sense.
$endgroup$
– Cowthulhu
8 hours ago
2
$begingroup$
@Hearth: that's interesting. I'd call them "hot" and "the other hot"!
$endgroup$
– TimWescott
8 hours ago
$begingroup$
@TimWescott Probably a better convention! But it is worth knowing that "cold" does not mean safe.
$endgroup$
– Hearth
7 hours ago
add a comment |
$begingroup$
In other words, it's kind of like a balanced three-phase system that has no neutral current and does not require a neutral, except instead of three phases there are only two.
$endgroup$
– DKNguyen
8 hours ago
$begingroup$
Note that the phases are sometimes called "hot" and "cold", though that should not be assumed to mean that "cold" is any less dangerous than hot.
$endgroup$
– Hearth
8 hours ago
$begingroup$
Thanks - that makes perfect sense.
$endgroup$
– Cowthulhu
8 hours ago
2
$begingroup$
@Hearth: that's interesting. I'd call them "hot" and "the other hot"!
$endgroup$
– TimWescott
8 hours ago
$begingroup$
@TimWescott Probably a better convention! But it is worth knowing that "cold" does not mean safe.
$endgroup$
– Hearth
7 hours ago
$begingroup$
In other words, it's kind of like a balanced three-phase system that has no neutral current and does not require a neutral, except instead of three phases there are only two.
$endgroup$
– DKNguyen
8 hours ago
$begingroup$
In other words, it's kind of like a balanced three-phase system that has no neutral current and does not require a neutral, except instead of three phases there are only two.
$endgroup$
– DKNguyen
8 hours ago
$begingroup$
Note that the phases are sometimes called "hot" and "cold", though that should not be assumed to mean that "cold" is any less dangerous than hot.
$endgroup$
– Hearth
8 hours ago
$begingroup$
Note that the phases are sometimes called "hot" and "cold", though that should not be assumed to mean that "cold" is any less dangerous than hot.
$endgroup$
– Hearth
8 hours ago
$begingroup$
Thanks - that makes perfect sense.
$endgroup$
– Cowthulhu
8 hours ago
$begingroup$
Thanks - that makes perfect sense.
$endgroup$
– Cowthulhu
8 hours ago
2
2
$begingroup$
@Hearth: that's interesting. I'd call them "hot" and "the other hot"!
$endgroup$
– TimWescott
8 hours ago
$begingroup$
@Hearth: that's interesting. I'd call them "hot" and "the other hot"!
$endgroup$
– TimWescott
8 hours ago
$begingroup$
@TimWescott Probably a better convention! But it is worth knowing that "cold" does not mean safe.
$endgroup$
– Hearth
7 hours ago
$begingroup$
@TimWescott Probably a better convention! But it is worth knowing that "cold" does not mean safe.
$endgroup$
– Hearth
7 hours ago
add a comment |
$begingroup$
tl; dr: You should install a NEMA 14-50 (4-wire: L1/L2, Neutral and Ground) instead of NEMA 6-50 for best flexibility. NEMA 14-50 is the standard 'dryer' plug now, and it's what a car charger uses too.
By the way, if you're messing with this, please consult an electrician. The fact that you're asking this at all makes me all kinds of worried.
Now, to the question. A 240V-only device has no need for a neutral since the load is connected across both ‘hot’ legs. So the current is always in balance, thus no need for a neutral to carry any imbalance. You will sometimes find this kind of wiring on high-power appliances like water heaters, ovens and fixed A/C units: two hots L1 and L2, and a Ground.
Plug-ins like dryers and electric ranges? That's a confusing story - sometimes there's just Neutral and sometimes Neutral and Ground. At the risk of drifting into DIY-land... more below.
3-wire vs. 4-wire 240V
Historically in the U.S. there have been two different types of high-current plug-in 240V appliance wiring: "3-wire" and "4-wire".
3-wire 240V has L1, L2 (hot) and Neutral. Appliances like dryers and ranges were allowed to connect Neutral to frame ground, so effectively the Neutral was serving as safety ground and carrying imbalance current if the appliance also used 120V.
Sound sketchy? It is. Even when things are working properly, when an appliance uses both 240V and 120V, the Neutral will have a small AC voltage on it due to the IR drop of the wire carrying the imbalance current. But when things go bad - say, for some reason Neutral opens up due to a flaky connection - you will have full 120V on the chassis. Not safe at all.
To remedy this fault, newer (since '96) 240V wiring uses the 4-wire system with L1, L2 (Hot), Neutral and Ground. Neutral is optional, only if the appliance needs a split 120 feed (say, for a dual-wattage heating element or a controller that runs on 120V), but it always gets a Ground. This enforces the idea that safety ground never carries current except when there's a fault, which isn't possible with the 3-wire L1/L2/Neutral setup.
More about the two 240V wiring types here: https://fredsappliance.com/service/3-prong-vs-4-prong-dryer-outlets-whats-the-difference/
And here: https://www.jadelearning.com/3-wire-cords-on-modern-4-wire-appliances/
Either way, at the panel the two hot legs L1/L2 are referred back to Neutral, as well as to safety ground. L1/L2 will have a duplex panel breaker, one breaker for each leg. The duplex breaker ensures that a hot-to-ground, hot-to-neutral or hot-to-hot fault in either leg will trip both breakers.
answered 8 hours ago
hacktasticalhacktastical
2,6414 silver badges12 bronze badges
$endgroup$
add a comment |
$begingroup$
tl; dr: You should install a NEMA 14-50 (4-wire: L1/L2, Neutral and Ground) instead of NEMA 6-50 for best flexibility. NEMA 14-50 is the standard 'dryer' plug now, and it's what a car charger uses too.
By the way, if you're messing with this, please consult an electrician. The fact that you're asking this at all makes me all kinds of worried.
Now, to the question. A 240V-only device has no need for a neutral since the load is connected across both ‘hot’ legs. So the current is always in balance, thus no need for a neutral to carry any imbalance. You will sometimes find this kind of wiring on high-power appliances like water heaters, ovens and fixed A/C units: two hots L1 and L2, and a Ground.
Plug-ins like dryers and electric ranges? That's a confusing story - sometimes there's just Neutral and sometimes Neutral and Ground. At the risk of drifting into DIY-land... more below.
3-wire vs. 4-wire 240V
Historically in the U.S. there have been two different types of high-current plug-in 240V appliance wiring: "3-wire" and "4-wire".
3-wire 240V has L1, L2 (hot) and Neutral. Appliances like dryers and ranges were allowed to connect Neutral to frame ground, so effectively the Neutral was serving as safety ground and carrying imbalance current if the appliance also used 120V.
Sound sketchy? It is. Even when things are working properly, when an appliance uses both 240V and 120V, the Neutral will have a small AC voltage on it due to the IR drop of the wire carrying the imbalance current. But when things go bad - say, for some reason Neutral opens up due to a flaky connection - you will have full 120V on the chassis. Not safe at all.
To remedy this fault, newer (since '96) 240V wiring uses the 4-wire system with L1, L2 (Hot), Neutral and Ground. Neutral is optional, only if the appliance needs a split 120 feed (say, for a dual-wattage heating element or a controller that runs on 120V), but it always gets a Ground. This enforces the idea that safety ground never carries current except when there's a fault, which isn't possible with the 3-wire L1/L2/Neutral setup.
More about the two 240V wiring types here: https://fredsappliance.com/service/3-prong-vs-4-prong-dryer-outlets-whats-the-difference/
And here: https://www.jadelearning.com/3-wire-cords-on-modern-4-wire-appliances/
Either way, at the panel the two hot legs L1/L2 are referred back to Neutral, as well as to safety ground. L1/L2 will have a duplex panel breaker, one breaker for each leg. The duplex breaker ensures that a hot-to-ground, hot-to-neutral or hot-to-hot fault in either leg will trip both breakers.
answered 8 hours ago
hacktasticalhacktastical
2,6414 silver badges12 bronze badges
$endgroup$
add a comment |
$begingroup$
tl; dr: You should install a NEMA 14-50 (4-wire: L1/L2, Neutral and Ground) instead of NEMA 6-50 for best flexibility. NEMA 14-50 is the standard 'dryer' plug now, and it's what a car charger uses too.
By the way, if you're messing with this, please consult an electrician. The fact that you're asking this at all makes me all kinds of worried.
Now, to the question. A 240V-only device has no need for a neutral since the load is connected across both ‘hot’ legs. So the current is always in balance, thus no need for a neutral to carry any imbalance. You will sometimes find this kind of wiring on high-power appliances like water heaters, ovens and fixed A/C units: two hots L1 and L2, and a Ground.
Plug-ins like dryers and electric ranges? That's a confusing story - sometimes there's just Neutral and sometimes Neutral and Ground. At the risk of drifting into DIY-land... more below.
3-wire vs. 4-wire 240V
Historically in the U.S. there have been two different types of high-current plug-in 240V appliance wiring: "3-wire" and "4-wire".
3-wire 240V has L1, L2 (hot) and Neutral. Appliances like dryers and ranges were allowed to connect Neutral to frame ground, so effectively the Neutral was serving as safety ground and carrying imbalance current if the appliance also used 120V.
Sound sketchy? It is. Even when things are working properly, when an appliance uses both 240V and 120V, the Neutral will have a small AC voltage on it due to the IR drop of the wire carrying the imbalance current. But when things go bad - say, for some reason Neutral opens up due to a flaky connection - you will have full 120V on the chassis. Not safe at all.
To remedy this fault, newer (since '96) 240V wiring uses the 4-wire system with L1, L2 (Hot), Neutral and Ground. Neutral is optional, only if the appliance needs a split 120 feed (say, for a dual-wattage heating element or a controller that runs on 120V), but it always gets a Ground. This enforces the idea that safety ground never carries current except when there's a fault, which isn't possible with the 3-wire L1/L2/Neutral setup.
More about the two 240V wiring types here: https://fredsappliance.com/service/3-prong-vs-4-prong-dryer-outlets-whats-the-difference/
And here: https://www.jadelearning.com/3-wire-cords-on-modern-4-wire-appliances/
Either way, at the panel the two hot legs L1/L2 are referred back to Neutral, as well as to safety ground. L1/L2 will have a duplex panel breaker, one breaker for each leg. The duplex breaker ensures that a hot-to-ground, hot-to-neutral or hot-to-hot fault in either leg will trip both breakers.
answered 8 hours ago
hacktasticalhacktastical
2,6414 silver badges12 bronze badges
$endgroup$
tl; dr: You should install a NEMA 14-50 (4-wire: L1/L2, Neutral and Ground) instead of NEMA 6-50 for best flexibility. NEMA 14-50 is the standard 'dryer' plug now, and it's what a car charger uses too.
By the way, if you're messing with this, please consult an electrician. The fact that you're asking this at all makes me all kinds of worried.
Now, to the question. A 240V-only device has no need for a neutral since the load is connected across both ‘hot’ legs. So the current is always in balance, thus no need for a neutral to carry any imbalance. You will sometimes find this kind of wiring on high-power appliances like water heaters, ovens and fixed A/C units: two hots L1 and L2, and a Ground.
Plug-ins like dryers and electric ranges? That's a confusing story - sometimes there's just Neutral and sometimes Neutral and Ground. At the risk of drifting into DIY-land... more below.
3-wire vs. 4-wire 240V
Historically in the U.S. there have been two different types of high-current plug-in 240V appliance wiring: "3-wire" and "4-wire".
3-wire 240V has L1, L2 (hot) and Neutral. Appliances like dryers and ranges were allowed to connect Neutral to frame ground, so effectively the Neutral was serving as safety ground and carrying imbalance current if the appliance also used 120V.
Sound sketchy? It is. Even when things are working properly, when an appliance uses both 240V and 120V, the Neutral will have a small AC voltage on it due to the IR drop of the wire carrying the imbalance current. But when things go bad - say, for some reason Neutral opens up due to a flaky connection - you will have full 120V on the chassis. Not safe at all.
To remedy this fault, newer (since '96) 240V wiring uses the 4-wire system with L1, L2 (Hot), Neutral and Ground. Neutral is optional, only if the appliance needs a split 120 feed (say, for a dual-wattage heating element or a controller that runs on 120V), but it always gets a Ground. This enforces the idea that safety ground never carries current except when there's a fault, which isn't possible with the 3-wire L1/L2/Neutral setup.
More about the two 240V wiring types here: https://fredsappliance.com/service/3-prong-vs-4-prong-dryer-outlets-whats-the-difference/
And here: https://www.jadelearning.com/3-wire-cords-on-modern-4-wire-appliances/
Either way, at the panel the two hot legs L1/L2 are referred back to Neutral, as well as to safety ground. L1/L2 will have a duplex panel breaker, one breaker for each leg. The duplex breaker ensures that a hot-to-ground, hot-to-neutral or hot-to-hot fault in either leg will trip both breakers.
answered 8 hours ago
hacktasticalhacktastical
2,6414 silver badges12 bronze badges
edited 55 mins ago
answered 8 hours ago
hacktasticalhacktastical
2,6414 silver badges12 bronze badges
answered 8 hours ago
hacktasticalhacktastical
2,6414 silver badges12 bronze badges
answered 8 hours ago
hacktasticalhacktastical
2,6414 silver badges12 bronze badges
2,6414 silver badges12 bronze badges
add a comment |
add a comment |
$begingroup$
A 240v electric water heater has the same type of wiring, 2 120v legs and a ground, as do most residential air conditioners and ovens. If the appliance doesn't need 120v for anything then they don't need the neutral.
answered 7 hours ago
JACKJACK
1684 bronze badges
$endgroup$
add a comment |
$begingroup$
A 240v electric water heater has the same type of wiring, 2 120v legs and a ground, as do most residential air conditioners and ovens. If the appliance doesn't need 120v for anything then they don't need the neutral.
answered 7 hours ago
JACKJACK
1684 bronze badges
$endgroup$
add a comment |
$begingroup$
A 240v electric water heater has the same type of wiring, 2 120v legs and a ground, as do most residential air conditioners and ovens. If the appliance doesn't need 120v for anything then they don't need the neutral.
answered 7 hours ago
JACKJACK
1684 bronze badges
$endgroup$
A 240v electric water heater has the same type of wiring, 2 120v legs and a ground, as do most residential air conditioners and ovens. If the appliance doesn't need 120v for anything then they don't need the neutral.
answered 7 hours ago
JACKJACK
1684 bronze badges
answered 7 hours ago
JACKJACK
1684 bronze badges
answered 7 hours ago
JACKJACK
1684 bronze badges
answered 7 hours ago
JACKJACK
1684 bronze badges
1684 bronze badges
add a comment |
add a comment |
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$begingroup$
"Live/hot" should be merely be taken to mean "anything that is not at ground", whereas "neutral" should be taken to mean "any that return current goes through that is tied to ground somewhere". It's just that on a wall outlet, the plug that return currents travel on which would otherwise also be "live" has been tied to ground for safety purposes making it the neutral.
$endgroup$
– DKNguyen
8 hours ago
$begingroup$
Also note that just because the neutral is connected to ground doesn't mean it necessarily sits at ground. The neutral's connection to ground may be very far away from where you are and the resulting impedance can make the neutral voltage rise if there are currents.
$endgroup$
– DKNguyen
8 hours ago